Custom elastomeric earmold with secondary material infusion

ABSTRACT

A method of manufacturing a custom elastomeric earmold with a secondary material infusion and said custom elastomeric earmold is disclosed. The method can include establishing a representation of a shape of the ear concha, the outer canal and the inner ear canal cavity. The method may further include casting a custom shaped injection mold. The injection mold may be used to cast a custom shape of the inner and outer ear from an elastomeric material such as silicone or urethane. An additional injection step can be performed to infuse foam into the interior of the elastomeric material.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 62/327,723 filed Apr. 26, 2016 entitled “Custom Elastomeric Earmold with Secondary Material Infusion” which is hereby incorporated herein by reference in its entirety.

FIELD

Embodiments presented herein pertain generally to customizable elastomeric earmolds used in both active sound processing units (hearing aids, earphones) and passive devices (earplugs, swim plugs). More particularly, embodiments presented herein pertain to a method of manufacture for a custom composite elastomeric earmold (and said earmold) that is comprised of an outer soft biocompatible material infused with a secondary compatible, compressible and/or soft material to achieve added softness and compliance in specific areas.

BACKGROUND

Many sound producing (hearing aids and earphones) and hearing protective (earplugs and musician plugs) devices generally require: (1) that the device provides a good acoustic seal which is important for device performance and sound quality, and 2) that the device fits comfortably in the ear. There are many concepts for achieving this through the use of a variety of materials including elastomers and foams in a variety of shapes, sizes and processes.

Foam has an advantage over monolithic or solid materials in applications requiring compliance and comfort of an item in contact with a human. Foam is commonly used to enhance comfort in products ranging from furniture to shoes to helmets. Foam has also been used in earplugs for decades, but generally in pre-molded form. See Leight (U.S. Pat. No. 4,774,938 A). Foam has also been applied to earmolds to improve comfort and also to improve performance by providing a better acoustic seal (e.g. Staab (WO2008157557 A1)).

Foam, however, has some limitations with regard to custom earmold applications due to problems associated with known production methods (short working times, limitation of material selection) and customer use associated with insertion (the foam is too flaccid to allow insertion), cleanliness (foams allow foreign material to become trapped in the foam cells) and strength (the tear strength of foam limits its ability to be removed from the ear if the mold fits too tight or is handled too roughly). Due to these limitations, most custom soft earmoulds are made from monolithic elastomers (silicone, PVC and urethane) rather than foam.

Various attempts have been made to provide a combination of silicone and foam, or urethane and foam, in order to take advantage of the beneficial properties of each (see e.g. Parkins (US20120243701 A1), Staab, Keady (WO2010094034 A1 and WO2011163565 A1), Gebert (WO2012007193 A1) and Stonikas (US20020025055 A1)). However, in such instances, the foam is added as a separate piece of the mold using some assembly process. In particular, in known examples of composite devices, the elastomeric part and the foam part are added as separate items with the foam piece added to the elastomer in a secondary operation such as described by Parkins. Alternative processes involve pumping foam into an inflatable container such as described in Staab, Keady (WO2010094034 A1 and WO2011163565 A1), Gebert and Stonikas. In non-custom ear tip applications, foam is used by itself or combined with other pre-molded items to form a more complex device. See Purcell (U.S. Pat. No. 7,984,716 B2). A multi-material concept for earplugs is generally described by Parkins (US20110271965 A1), but in that case there is no mention of infusion of the secondary material during the casting operation, nor is there a description of the system for dispersing and controlling the infused material.

Digital processes common to the manufacture of hearing aid products are generally known and disclosed in Topholm (U.S. Pat. No. 5,487,012), Martin (US20060239481) and Clausen (U.S. Pat. No. 8,032,337). Topholm and Clausen generally describe the advent of digital data processing and 3D Printing (rapid prototyping) in the custom earmold industry. Such advancements created the ability to add sophisticated features to a custom product while maintaining a reasonable, machine based fabrication. In Martin, for example, the process of casting custom elastomeric molds using a single use 3D printed mold is generally described. In particular, according to the teachings of Martin, a 3D mold can be used as a single use injection mold for a variety of material.

Thus, there is a need in the art for an improved method for combining foam and silicone in a custom application by using casting techniques provided by 3D printing. There is further a need in the art for an improved composite sound processing device/product (and method of manufacturing same) that can be formed from a variety of materials to enhance the properties, performance and appearance of the resulting earmold. There is further a need in the art for a composite sound processing device that can incorporate a secondary casting operation which can infuse foam (or other soft, compressible material) into the interior of an outer elastomeric casting to achieve softness and compliance in specific areas. There is also generally a need in the art for a composite earmold that can demonstrate excellent retention in the ear due to the outer ear customization, improved compliance to move as the ear canal moves, improved comfort, increased flexibility, excellent acoustic seal and a deeper seal resulting in reduced occlusion in the ear canal.

SUMMARY OF THE INVENTION

Embodiments of the subject invention represent an advancement beyond known processes in that they can incorporate a secondary casting operation which can infuse the foam into the interior of the elastomeric casting. In particular, in addition to injecting a primary elastomer, an additional process step can be performed to add a secondary interior material that can be fully contained within the primary elastomer. The process can take advantage of the surface tension effect of the primary material to stay adhered to the interior side of the walls of the mold. This can allow the secondary material to occupy the interior without displacing the base elastomer from the exterior.

An elastomeric composite system according to embodiments presented herein is unique in that the foam can be an integral part of casting process. Thus, embodiments presented herein move beyond known technologies and processes by enabling the creation of an earmold having a specialized exterior shape and also a specialized interior made from compatible foam. Such innovations represent and incorporate new design elements and fabrication methods in custom earmold and hearing aid shell design and fabrication.

The result is an earmold with localized softness and compliancy that surpasses previous art by achieving higher degrees of comfort, improved acoustic seal, and by allowing a deeper fit in the ear canal can prevent occlusion effects. Specifically, the combination of the material and novel design concepts disclosed herein can provide numerous benefits, including for example: (1) creating a product with excellent retention in the ear due to the outer ear customization; (2) creating a product with improved compliance to move as the ear canal moves, improved comfort, increased flexibility, excellent acoustic seal and a deeper seal resulting in reduced occlusion in the ear canal. Such improvement can be attributable to the foam infused areas that are softer, more compressible, but springier than a solid elastomeric material and, therefore, enabling the design to become more accommodating to the dynamics of the canal when compared to full custom molds. The light spring force of the foam material can provide an improved acoustic seal without discomfort; (3) creating a comfortable product with improved and deeper acoustic seal over a full custom product as the silicone/silicone foam combination provides a compliant seal that does not break when the wearer moves his head or jaw. Thus, the innovation presented herein can greatly improve the performance of any in-ear product including, but not exclusive to: 1) hearing aids, 2) hearing protection, and 3) custom earphones.

Embodiments set forth herein can consist of a custom mold for the ear where the custom portion is confined to the outer ear and entry to the canal only. Specifically, the mold can be made from injecting an elastomeric material into a one use injection made in a 3D printing process (Martin). Any portion of the mold can be enhanced through the infusion of a secondary material which displaces the original material from only the interior of the mold due to the surface tension characteristics of the primary elastomeric material which keep the primary material adhered to the injection mold surface. Accordingly, embodiments of the subject invention can make use of the surface tension involved in the elastomer casting process. For example, when an elastomer is injected into a 3D printed one-shot injection mold, the surface tension of the original, or primary, material can cause the elastomer to adhere to the surface of the mold. When any secondary material (such as another elastomer, air, water, other liquids, pastes or foam) possessing the characteristic of fluidity is injected into the mold it cannot displace the original material from the surface of the mold; it can only displace it from the interior of the mold. This means that the original elastomer will remain along the outside surface of the mold and can form the outer “skin” or “layer” of the final device; while the secondary material will form the interior of the device.

There is a variety of process controls available that can provide for control of both the location and amount of the residual primary material and the secondary infused material. A few examples are:

-   -   1. The timing of the primary material curing and the secondary         material infusion. If the curing of the primary material is time         dependent, then the thickness of the outer layer of primary         material can be controlled by time. Since the curing of the         primary material, if it is a two-part catalyst curing system, is         a function of time. The same can be accomplished by heat         exposure with a heat dependent primary material.     -   2. The use of specialized sprues and vents in the injection         molding process. Placement and shape of sprues and vents can         control the injection process and can determine the location and         volume of each material during injection.     -   3. The evacuation of the primary material before the infusion of         the secondary material. In this case, the primary material is         removed by using pressurized air or liquid, such as water, that         acts as a temporary displacement of the primary material prior         to the infusion of the final secondary material.

Utilizing the abilities of application specific software and 3D printing, an earmold is now a sophisticated composite structure combining a variety of materials to enhance the properties, performance and appearance of the resulting earmold. Again utilizing the abilities of application specific software and 3D printing, interior features are no longer limited to a set arrangement of interior spaces.

Embodiments disclosed herein can additionally provide an improved method for combining foam and silicone in a custom application by using the casting techniques provided by 3D printing. As discussed in Martin, a 3D mold can be used as a single use injection mold for a variety of material. The subject invention can incorporate the same concept of the one shot mold, but can additionally rely on the concept of a secondary infusion of material to create a composite mold of both the primary material injected in the mold and the secondary material injected in the mold. The process can also utilize the chemical characteristic of surface tension to maintain the primary material as the “outer” skin or layer of the final device, while limiting the secondary material to the interior of the device. In this way, the outer layer can maintain the advantages of the primary material while the interior can maintain the advantages of the secondary material.

The combination of materials can be unlimited as long as they are chemically compatible and can be injected into a 3D printed mold. Examples of some combinations can include, for instance

-   -   Primary: silicone Secondary: silicone foam     -   Primary: silicone of hardness A, Secondary: silicone of a         different hardness     -   Primary: silicone, Secondary: silicone gel     -   Primary: silicone, Secondary: silicone of another color     -   Primary: urethane Secondary: urethane foam     -   Primary: urethane of hardness A, Secondary: urethane of a         different hardness     -   Primary: urethane, Secondary: urethane gel     -   Primary: urethane, Secondary: urethane of another color     -   Primary: urethane or urethane and urethane foam     -   Primary: silicone, secondary: air     -   Primary: silicone, secondary: a compatible liquid

A composite mold has the advantage of combining the desirable properties of both materials. For example, the silicone (primary) and silicone foam (secondary) composite has the advantage of the softness and compliance of the foam, but has the stiffness, strength and chemical stability of silicone. This results in an earmold of superior performance since it is very comfortable due to the foam, can go deep in the ear because of this comfort, will provide a better acoustic seal due to the compliance of the foam, but due to the stiffness of the silicone outer layer the earmold can be inserted easily, provides a biologically compatible surface, is easily cleaned and provides durable performance regarding tear strength and chemical resistance.

The composite earmold described herein can accomplish numerous benefits, including for example: 1) achieving a better acoustic seal than a tight-fitting, full custom canal due to the improved compliance (softness) and shape changing abilities of foam; 2) improving the comfort of the device for the same reasons of improved compliance and shape changing while forgiving incomplete ear impressions; 3) extending deeper into the canal due to the improved softness and flexibility which has the advantages of reducing the occlusion effect; 4) achieving lower noise levels associated with jaw movement and leaks associated with the continual loss and regain of an acoustic seal experienced using a tight fitting, monolithic material.

Another advantage of the molding process that entraps the secondary material on the interior of the mold is the allowance of liquids or gels as the secondary material. This can allow the use of superior acoustic dampening caused by a variety of material choices (see e.g. Parkins US20110271965 A1).

The custom injection mold and casting can be performed using processes common to the hearing aid industry. Custom injection mold and casting processes as well as 3D printing process used to make injection molds are generally well-known and common to the hearing aid industry. In addition, processes used to prepare molds, fill molds with soft biocompatible material such as silicone, or remove the silicone from the molds are also generally known. See e.g. Martin (US20060239481), Mcleod (WO2011044903).

In this case, the shape of a person's ear can be acquired through the injection of silicone into the ear and ear canal, or the outer ear and canal entry areas can be scanned with a laser or white light scanner. The scanned image can be used to fashion, or sculpt, the final shape of the product, and to add predesigned features to the mold that are merged into the digital image of the mold. A digital file of the final product design can then be output to a 3D Rapid Prototyping/Manufacturing machine. In this process, the object that is made on the 3D printer can be an injection mold which is then filled with silicone (Martin). Once the silicone cures, the outer “shell” of the mold can be cracked open and removed to reveal the silicone mold on the inside.

The capture of the image of a person's ear and the use of software to design an earmold are generally known. However, embodiments described herein can incorporate novel objects used within the software to add complexity to the injection mold and earmold design. As described herein, one unique/novel object that can be added to the earmold design can be the injection mold sprue system: 1) a pre-designed shape which is chosen and located to optimize the amount and position of the secondary material, this is usually in the canal area but can also be in the outer ear area where the ear moves or is pressed upon when the wearer rests one side of the head against a surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a posterior section of an ear impression captured with digital 3D scanning according to an exemplary embodiment.

FIG. 1B is a perspective view of an anterior section of the ear impression of FIG. 1A.

FIG. 2A is a perspective view of a first pre-designed sprue according to an exemplary embodiment.

FIG. 2B is a perspective view of a second pre-designed sprue according to an exemplary embodiment.

FIG. 3A is a first perspective view of an injection mold for creation of a composite mold according to an exemplary embodiment.

FIG. 3B is a second perspective view of the injection mold of FIG. 3A.

FIG. 3C is a second perspective view of the injection mold of FIG. 3A.

FIG. 4 is a partial cross section view of an injection mold according to an exemplary embodiment.

FIG. 5 is a partial cross section view of the injection mold showing an earmold according to an exemplary embodiment.

FIG. 6A is a first perspective view of a composite device according to an exemplary embodiment.

FIG. 6B is a second perspective view of the composite device of FIG. 6A.

FIG. 7A is a perspective view of the inferior side of a composite device according to an exemplary embodiment.

FIG. 7B is a partial cross section view through the anterior portion of the composite device of FIG. 7A.

FIG. 8A is a perspective view of a composite device according to an exemplary embodiment.

FIG. 8B is a partial cross section view of the composite device of FIG. 8A.

FIG. 9 is a detail cross section view through the canal portion of the composite device of FIGS. 8A and 8B.

FIG. 10A is a perspective view of a single use injection mold according to an exemplary embodiment.

FIG. 10B is a perspective partial cutaway view of the single use injection mold of FIG. 10A.

FIG. 11 is a perspective partial cutaway view of a single use injection mold filled with a primary material according to an exemplary embodiment.

FIG. 12 is a perspective partial cutaway view of a single use injection mold showing a hollow interior area of the primary material displaced with air or water according to an exemplary embodiment.

FIG. 13 is a perspective partial cutaway view of a single use injection mold showing the secondary material filling the hollow interior area of the primary material according to an exemplary embodiment.

FIG. 14 is a graphical flowchart of a process according to an exemplary embodiment.

FIG. 15 is a graphical flowchart of a process according to an exemplary embodiment.

DETAILED DESCRIPTION

While the subject invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in specific detail, embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

Embodiments presented herein are directed to a new process for custom elastomeric earmolds used in both active sound processing units (hearing aids, earphones) and passive devices (earplugs, swim plugs) which can create a product that is made from soft, biocompatible material such as silicone or urethane that can be infused with compatible, compressible foam, or other soft materials, in order to achieve softness and compliance in specific areas on the earmold. The result is an earmold with localized softness and compliancy that surpasses previous art by achieving higher degrees of comfort, improved acoustic seal, and by allowing a deeper fit in the ear canal can prevent occlusion effects.

The combination of the material and novel design concepts can provide numerous benefits, including for example: (1) creating a product with excellent retention in the ear due to the outer ear customization; (2) creating a product with improved compliance to move as the ear canal moves, improved comfort, increased flexibility, excellent acoustic seal and a deeper seal resulting in reduced occlusion in the ear canal. This improvement can be attributable to the foam infused areas that are softer, more compressible, but springier than a solid elastomeric material and, therefore, enabling the design to become more accommodating to the dynamics of the canal when compared to full custom molds. The light spring force of the foam material can provide an improved acoustic seal without discomfort; (3) creating a comfortable product with improved and deeper acoustic seal over a full custom product as the silicone/silicone foam combination provides a compliant seal that does not break when the wearer moves his head or jaw.

Embodiments described herein can be created using digital processes common to the manufacture of hearing aid products. Such processes can be used to make a one-time mold for casting silicone or urethane elastomers, but in addition to injecting the primary elastomer, an additional process step can be performed to add a secondary interior material that can be fully contained within the primary elastomer. The process can take advantage of the surface tension effect of the primary material to stay adhered to the exterior walls of the mold. This can allow the secondary material to occupy the interior without displacing the base elastomer from the exterior.

It has been observed that embodiments disclosed herein can improve the performance of any in-ear product including, but not exclusive to: 1) hearing aids, 2) hearing protection, and 3) custom earphones.

According to an exemplary embodiment, a secondary casting operation can infuse a foam substance into the interior of the elastomeric casting. Thus, in addition to injecting a primary elastomer, an additional process step can be performed to add a secondary interior material that can be fully contained within the primary elastomer. The process can take advantage of the surface tension effect of the primary material to stay adhered to the exterior walls of the mold. This can allow the secondary material to occupy the interior without displacing the base elastomer from the exterior.

Embodiments set forth herein can consist of a custom mold for the ear where the custom portion is confined to the outer ear and entry to the canal only. Specifically, the mold can be made from injecting an elastomeric material into a one use injection made in a 3D printing process. Any portion of the mold can be enhanced through the infusion of a secondary material which displaces the original material from only the interior of the mold due to the surface tension characteristics of the primary elastomeric material which keep the primary material adhered to the injection mold surface. Accordingly, embodiments of the subject invention can make use of the surface tension involved in the elastomer casting process. For example, when an elastomer is injected into a 3D printed one-shot injection mold, the surface tension of the original, or primary, material can cause the elastomer to adhere to the surface of the mold. When any secondary material (such as another elastomer, air, water, other liquids, pastes or foam) possessing the characteristic of fluidity is injected into the mold it cannot displace the original material from the surface of the mold; it can only displace it from the interior of the mold. This means that the original elastomer will remain along the outside surface of the mold and can form the outer “skin” or “layer” of the final device; while the secondary material will form the interior of the device.

There is a variety of process controls available that can provide for control of both the location and amount of the residual primary material and the secondary infused material. A few examples are:

-   -   1. The timing of the primary material curing and the secondary         material infusion. If the curing of the primary material is time         dependent, then the thickness of the outer layer of primary         material can be controlled by time. Since the curing of the         primary material, if it is a two-part catalyst curing system, is         a function of time. The same can be accomplished by heat         exposure with a heat dependent primary material.     -   2. The use of specialized sprues and vents in the injection         molding process. Placement and shape of sprues and vents can         control the injection process and can determine the location and         volume of each material during injection.     -   3. The evacuation of the primary material before the infusion of         the secondary material. In this case, the primary material is         removed by using pressurized air or liquid, such as water, that         acts as a temporary displacement of the primary material prior         to the infusion of the final secondary material.

Utilizing the abilities of application specific software and 3D printing, an earmold is now a sophisticated composite structure combining a variety of materials to enhance the properties, performance and appearance of the resulting earmold. Again utilizing the abilities of application specific software and 3D printing, interior features are no longer limited to a set arrangement of interior spaces.

Embodiments disclosed herein can additionally provide an improved method for combining foam and silicone in a custom application by using the casting techniques provided by 3D printing. For example, embodiments disclosed herein can incorporate the known concept of a one-shot mold, but can additionally rely on the concept of a secondary infusion of material to create a composite mold of both the primary material injected in the mold and the secondary material injected in the mold. The process can also utilize the chemical characteristic of surface tension to maintain the primary material as the “outer” skin or layer of the final device, while limiting the secondary material to the interior of the device. In this way, the outer layer can maintain the advantages of the primary material while the interior can maintain the advantages of the secondary material.

The combination of materials can be unlimited as long as they are chemically compatible and can be injected into a 3D printed mold. Examples of some combinations can include, for instance

-   -   Primary: silicone Secondary: silicone foam     -   Primary: silicone of hardness A, Secondary: silicone of a         different hardness     -   Primary: silicone, Secondary: silicone gel     -   Primary: silicone, Secondary: silicone of another color     -   Primary: urethane Secondary: urethane foam     -   Primary: urethane of hardness A, Secondary: urethane of a         different hardness     -   Primary: urethane, Secondary: urethane gel     -   Primary: urethane, Secondary: urethane of another color     -   Primary: urethane or urethane and urethane foam     -   Primary: silicone, secondary: air     -   Primary: silicone, secondary: a compatible liquid

A composite mold has the advantage of combining the desirable properties of both materials. For example, the silicone (primary) and silicone foam (secondary) composite has the advantage of the softness and compliance of the foam, but has the stiffness, strength and chemical stability of silicone. This results in an earmold of superior performance since it is very comfortable due to the foam, can go deep in the ear because of this comfort, will provide a better acoustic seal due to the compliance of the foam, but due to the stiffness of the silicone outer layer the earmold can be inserted easily, provides a biologically compatible surface, is easily cleaned and provides durable performance regarding tear strength and chemical resistance.

The composite earmold described herein can accomplish numerous benefits, including for example: 1) achieving a better acoustic seal than a tight-fitting, full custom canal due to the improved compliance (softness) and shape changing abilities of foam; 2) improving the comfort of the device for the same reasons of improved compliance and shape changing while forgiving incomplete ear impressions; 3) extending deeper into the canal due to the improved softness and flexibility which has the advantages of reducing the occlusion effect; 4) achieving lower noise levels associated with jaw movement and leaks associated with the continual loss and regain of an acoustic seal experienced using a tight fitting, monolithic material.

Another advantage of the molding process that entraps the secondary material on the interior of the mold is the allowance of liquids or gels as the secondary material. This can allow the use of superior acoustic dampening caused by a variety of material choices (see e.g. Parkins US20110271965 A1).

The custom injection mold and casting can be performed using processes common to the hearing aid industry. Custom injection mold and casting processes as well as 3D printing process used to make injection molds are generally well-known and common to the hearing aid industry. In addition, processes used to prepare molds, fill molds with soft biocompatible material such as silicone, or remove the silicone from the molds are also generally known.

In this case, the shape of a person's ear can be acquired through the injection of silicone into the ear and ear canal, or the outer ear and canal entry areas can be scanned with a laser or white light scanner. The scanned image can be used to fashion, or sculpt, the final shape of the product, and to add predesigned features to the mold that are merged into the digital image of the mold. A digital file of the final product design can then be output to a 3D Rapid Prototyping/Manufacturing machine. In this process, the object that is made on the 3D printer can be an injection mold which is then filled with silicone (Martin). Once the silicone cures, the outer “shell” of the mold can be cracked open and removed to reveal the silicone mold on the inside.

The capture of the image of a person's ear and the use of software to design an earmold are generally known. However, embodiments described herein can incorporate novel objects used within the software to add complexity to the injection mold and earmold design. As described herein, one unique/novel object that can be added to the earmold design can be the injection mold sprue system: 1) a pre-designed shape which is chosen and located to optimize the amount and position of the secondary material, this is usually in the canal area but can also be in the outer ear area where the ear moves or is pressed upon when the wearer rests one side of the head against a surface.

With reference now to the figures, FIGS. 1A and 1B show an exemplary ear impression 1 captured with digital 3D scanning. FIG. 1A shows a posterior section of the impression 1 and FIG. 1B shows an anterior section of the impression 1. Such an impression 1 can be a starting point image for creating custom earphone devices according to embodiments set forth herein. The impression 1 can then loaded into software specifically designed for creating custom earmold products from digitally scanned images—this process is generally known as eSculpting. eSculpting can alter the shape of the original image to adapt it to the shape of a final product (see e.g. FIGS. 6A and 6B, ref. no. 5). eSculpting can also be used to include CAD objects that can produce sprues for injecting primary and secondary materials into the mold.

FIGS. 2A and 2B show pre-designed sprues 2, 3 that can be used to inject materials into the mold to create composite custom earmold products according to exemplary embodiments. According to an exemplary embodiment as shown schematically, spure 2 shown in FIG. 2A can be used to inject the primary elastomeric material into the mold and spure 3 shown in FIG. 2B can be used to inject the secondary material into the mold.

FIGS. 3A through 3C and FIG. 4 show an exemplary hearing protection single use injection mold 4 according to embodiments of the subject invention. As shown schematically, the mold 4 can have at least two injection ports (shown as sprues 2, 3) to allow the creation of a composite earmold from two different materials such as soft and hard, or different color materials. For example, according to embodiments disclosed herein, injection sprue 2 can be used to inject a primary material into the single use injection mold and sprue 3 can be used to inject a secondary material into the single use injection mold.

FIG. 5 shows a silicone earmold 5 shown inside of the single use injection mold 4 according to an exemplary embodiment. According to an exemplary embodiment, FIG. 5 shows earmold 5 during the “demolding” step where the silicone earmold 5 can be removed from the mold 4. For example, once the earmold 5 cures, the outer “shell” of the mold 4 can be cracked open and removed to reveal the silicone earmold 5 on the inside.

FIGS. 6A-6B, 7A-7B and 8A-8B show a final earmold device 5 according to exemplary embodiments. According to exemplary embodiments, earmold device 5 can be made from a primary material of either silicone or silicone elastomer that is infused with an interior of a secondary material 6 such as foam, gel, or a elastomer of a different hardness or characteristic from the primary material.

FIGS. 7B, 8B and 9 show the location of the primary and secondary materials 6, 7 within earmold 5. As shown schematically in FIGS. 7B, 8B and 9, the primary material 6 can remains in areas where it was in contact with the injection mold wall, but is displaced in specific areas by the secondary material 7.

FIGS. 10A and 10B show the single use injection mold 4 according to an exemplary embodiment with a sections cutaway to show the interior area of the mold 4 where earmold 5 can be formed. FIG. 11 illustrates the mold 4 filled with the primary material 6 which can form the outer layer of the earmold. FIG. 12 shows mold 4 filled with primary material 6 and a hollow interior area 8. According to embodiments presented herein, an interior portion of the primary material 6 within mold 4 can be displaced with air or water to create the hollow interior area 8. FIG. 13 shows injection mold 4 filled with the evacuated primary material 6 forming a thin wall against the interior side of the mold 4 with the evacuated interior filled with secondary material 7 to form a compliant interior.

FIG. 14 illustrates a graphical flowchart illustrating an exemplary process of manufacturing a custom composite earmold device according to an exemplary embodiment where a secondary material is infused to displace a primary material. According to the process shown schematically in FIG. 14, a digital scan of an ear can be taken. This can be acquired through either a direct material cast of the ear cavity and shape which is then placed in a digital scanner, or the scanned image of the ear can be acquired by a direct scan of the ear by a hand held digital scanner.

The impression of the ear can then loaded into software specifically designed for creating custom earmold products from digitally scanned images via eSculpting. The eSculpting process can also use CAD software to sculpt a digital scan. A CAD module of the product silicone mold can then be created which includes the specialized sprue features for injecting primary and secondary materials into the mold.

The eSculpting process can ultimately create earmold 5 (see e.g. FIGS. 6A and 6B) which is a digital representation of the final ear mold. The software can also use the digital representation of the final earmold 5 to create the single use injection mold 4 by creating an offset of the final product object 5 that can make a hollow mold with the interior having the shape of the desired final product. It is during this process that the predesigned features of the injection sprues 2, 3 (see FIGS. 2A-2B, 3A-3B and 4) for both the primary and secondary materials can be created as well.

The digital files of the injection mold 4 (see FIGS. 3A and 4) can then be loaded into 3D printing software and prepared for the 3D printing process. The 3D printing process can be performed by any of a variety of 3D printers on the market today using a variety of materials. After printing, the mold 4 can be prepared for the injection molding process. According to exemplary embodiments, it is preferred that the mold material be chemically compatible with the elastomer used to make the ear mold 5. The primary material 6 can be injected into the mold 4 until the entire interior surface is covered (see e.g. FIG. 11). The amount of time allowed between the primary and the secondary injections can alter the material surface thickness of the primary material 6 if the primary material 6 curing reaction is time or temperature dependent.

According to the exemplary process illustrated in FIG. 14, a secondary material 7 can be injected into the injection mold 4 using only the sprues 3 intended for the secondary material 7. This can place the secondary material 7 in the specific locations chosen to optimize the performance of the mold and help to balance the flow of the material into specific areas of the single use injection mold 4 (see e.g. FIGS. 7B, 8B and 9). Time and injection pressure can also be used to affect the injection results. The materials 6, 7 can be allowed to reach a cured state after being injected into the mold.

FIG. 15 illustrates a graphical flowchart illustrating an second exemplary process of manufacturing a custom composite earmold device according to an exemplary embodiment where an alternate medium is used to displace the primary material before a secondary material is added or injected/infused. According to the process shown schematically in FIG. 15, an alternate medium such as compressed air or pressurized liquid can be used to evacuate the interior of the primary material 6—the secondary material 7 can be then injected into the injection mold through the sprues and can fill the evacuated interior 8 (see e.g. FIGS. 12-13). This alternative process can achieve more displacement of the primary material 6 allowing for more of the secondary material 7 in the final device interior 8. Time and injection pressure can also be used to affect the injection results. The materials 6, 7 can be allowed to reach a cured state after being injected into the mold.

According to the processes illustrated in FIGS. 14 and 15, the 3D printed mold 4 filled with cured primary and secondary material 6, 7 can then be fractured and removed in order to release the final elastomeric earmold 5 (see FIG. 5). Final treatments can be completed to the earmold 5 to make the final product. According to exemplary embodiments, the final product can consist of the primary material 6 which can maintain its position on the outside of the earmold 5, with the secondary material 7 encased within the primary material 6 (see FIGS. 7B, 8B and 9).

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Further, logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Other steps may be provided, or steps may be eliminated, from the described flows, and other components may be add to, or removed from the described embodiments. 

What is claimed is:
 1. A method comprising: establishing a digital representation of a shape of an ear concha, an outer ear canal and an inner ear canal cavity; casting a custom-shaped injection mold from the digital representation; casting a custom shape of the inner ear canal cavity and outer ear canal from an elastomeric material in the injection mold; infusing foam into an interior of the elastomeric material.
 2. The method as in claim 1 further comprising supplementing the injection mold with a specialized sprue and controlling a flow and placement of the foam infusion into the interior of the elastomeric material.
 3. The method as in claim 2 where infusing the foam into an interior of the elastomeric material comprises injecting the infused foam into an interior area of the elastomeric material to displace the elastomeric material from the interior area.
 4. A method as in claim 1 where the elastomeric material is at least one of silicone or urethane.
 5. A method as in claim 2 further comprising forming a canal area on the order of 5 mm past a second bend of an ear.
 6. A method as in claim 1 further comprising permitting an infusion of materials such as liquids and gels into a final device.
 7. A method as in claim 1 further comprising: applying a temporary infusion of materials comprising at least one of liquids and air into the injection mold to remove the elastomeric material and leave an evacuated interior, and permanently filling the evacuated interior with the secondary material comprising at least one of liquids and gels into the mold.
 8. A method of manufacturing a custom composite earmold comprising: establishing a digital representation of a shape of an ear concha, an outer ear canal and an inner ear canal cavity; casting a custom-shaped injection mold from the digital representation, the injection mold having a plurality of sprues for carrying materials having different properties; introducing a primary material into the injection mold through at least one of the plurality of injection sprues, and introducing a secondary material different from the primary material into the injection mold though a second one of the plurality of injection spures and into an interior area of the primary material, the primary material being around the perimeter of the interior area.
 9. The method of claim 8 where the primary material is a biocompatible material selected from a group consisting of silicone and urethane.
 10. The method of claim 8 where the primary materials is elastomeric.
 11. The method of claim 8 where the secondary material is a material that is softer than the primary material.
 12. The method of claim 8 where the secondary material is compressible foam.
 13. The method of claim 8 where the primary material has a greater surface tension than the secondary material and adheres to an interior side of a wall of the mold and the secondary material has more fluidity than the primary material, the secondary material only displacing the primary material in the interior area.
 14. The method of claim 8 further comprising controlling the flow and placement of the secondary material into the interior of the area, said controlling being carried out by the second one of the plurality of injection spures.
 15. The method of claim 8 where the earmold is comprised of a composite design comprising an outer portion formed by the primary material and an inner portion formed by the secondary material in a predetermined area, the composite design having more softness in the predetermined area than a conventional earmold comprised of only the primary material.
 16. The method of claim 8 further comprising evacuating the interior area by introducing a medium into the interior area before introducing the secondary material, the medium being introduced through one of the plurality of sprues.
 17. The method of claim 16 where the medium is at least one of compressed air and pressurized liquid.
 18. A custom composite earmold comprising: an outer skin layer comprised of a biocompatible elastomeric material; at least one interior area comprised of a compressible foam having greater softness than the elastomeric material, the at least one interior area surrounded by the elastomeric material, and the earmold being formed by: establishing a digital representation of a shape of an ear concha, an outer ear canal and an inner ear canal cavity; casting a custom-shaped injection mold from the digital representation, the injection mold having a plurality of sprues for carrying materials having different properties; introducing a primary material into the injection mold through at least one of the plurality of injection sprues, and introducing a secondary material different from the primary material into the injection mold though a second one of the plurality of injection spures and into the at least one interior area. 